Geochemical Characterization and Trace-Element Mobility Assessment for Metallic Mine Reclamation in Soils Affected by Mine Activities in the Iberian Pyrite Belt

Abstract

The geochemical characterization of the mine deposits and soils in metal mining areas is essential in order to develop an effective mine reclamation strategy. The determination of total potentially toxic element (PTE) content, together with the application of chemical extraction procedures, can give insight into the behavior of contaminants after the application of different mine reclamation solutions, as well as identify the areas where urgent action is needed. This work presents a practical application to the evaluation of the pollution potential of trace elements in soils affected by mining activities, to be used in metallic mine reclamation. The PTE behavior was assessed by single extractions in order to simulate four environmental conditions: PTE mobility under rainfall conditions, acid mine drainage, reducing conditions, and plant uptake. The spatial distribution of contaminants in the study area was evaluated by determination of PTE total content in soil samples. Trace elements with high natural mobility, such as Zn, appeared concentrated at water and sediment discharge areas, while As, Pb, and Cu contents were higher near the mine wastes. The results obtained after the extractions suggested that the highest PTE content was extracted in the complexing–reducing medium, due to the dissolution of secondary sulfates and Fe3+ oxyhydroxides and the subsequent release of PTEs associated with those mineral phases. Reclamation strategies applied in the study area should promote efficient water drainage, infiltration, and subsuperficial water circulation in order to maintain oxidant conditions in the soil. The methodology applied in this study may constitute a valuable tool to define the geochemical constraints in metal mining areas, as well as help to develop appropriate mine reclamation solutions.

Bioaccumulation of Mercury and Other Trace Elements in the Edible Holothurian Holothuria (Halodeima) atra in Relation to Gold Mining Activities in North Sulawesi, Indonesia

“…Regardless of the presence of gold mines and sediment pollution levels, in the present study, H. atra has been shown to bioaccumulate some trace elements, mainly mercury, arsenic and zinc, and copper and cadmium in the guts, which had higher overall bioaccumulation factors. The large variability of bioaccumulation factors between sites suggests differences in the bioavailability of the trace elements, which is primarily due to local environmental conditions, water chemistry, and sedimentary regimes, but also the geochemical form of the elements (Thomann et al, 1995;McAloon and Mason, 2003;Sańchez-Donoso et al, 2021). The transport of trace elements from the substrate to the body wall and guts in holothurian is mainly unknown.…”

“…After the discovery of the Minamata neurological disease, caused by severe Hg poisoning in the Minamata Bay (Japan) from a local chemical factory in the 1956 (Eto et al, 2010), numerous studies were carried out on the bioaccumulation and marine food web transfers of potentially toxic trace elements (e.g., Bryan and Langston, 1992;Wang, 2002;Gao and Chen, 2012;Li et al, 2017;Murillo-Cisneros et al, 2019). A large number of chemical and biological mediated processes can contribute to trace element mobilization from rocks and soils (e.g., Carrillo-Gonzaĺez et al, 2006;Sessitsch et al, 2013;Sańchez-Donoso et al, 2021). After being released from natural or anthropogenic sources like factories, mines, shipping, dumping, or harbors to the marine environment, soluble trace metal species are accumulated in sediments through physical, chemical, and biological processes.…”

Soil and Freshwater Bioassays to Assess Ecotoxicological Impact on Soils Affected by Mining Activities in the Iberian Pyrite Belt

“…Other PHEs that showed noteworthy concentration values were Cu (up to 1320 mg kg −1 in sample LOS6) and Zn (up to 546 mg kg −1 in sample LOS06). The high Fe2O3content, with concentrations reaching 13% in three samples (LOS06, LOS09 and LOS10) and Co (more than 700 mg kg −1 in LOS06, LOS09 and LOS10), should also be mentioned [7]. Mineralogical data acquired shows that the main phases are quartz (26-60%), phyllosilicates (30-47%, mainly mica-illite and chlorite) and feldspars (8-14%), with goethite (Fe 3+ O(OH)), jarosite/plumbojarosite (KFe 3+ 3(SO4)2(OH)6 and Pb0.5Fe 3+ 3(SO4)2(OH)6).…”

“…The most common soils are leptosols [ 12 ], characterized by an acid character, with pH values around 5.2, and low organic matter content. In some areas, poorly developed soils over the Alvalade basin detritic deposits are also present, characterized by a sandy texture, very limited organic matter content and a slightly acidic nature [ 7 ].…”

“…This environmental concern is especially relevant in areas suffering from historical metallic mining activities, where the application of less efficient mineral extraction and processing techniques, and the lack of environmental awareness and controls have left huge environmental liabilities [ 4 ]. This is the case in the Iberian Pyrite Belt (IPB), where approximately 150 years of modern mining has resulted in the generation of enormous volumes of metal-rich waste dumps [ 5 , 6 , 7 ].…”